1. Field of the Invention
The present invention generally relates to a fuel cell system. More specifically, the present invention relates to a fuel cell system for supplying power to electronic musical instruments and PA systems.
Priorities are claimed on Japanese Patent Applications No. 2006-335495, filed Dec. 13, 2006, and No. 2007-098218, filed Apr. 4, 2007, the contents of which are incorporated herein by reference.
2. Description of the Related Art
All patents, patent applications, patent publications, scientific articles, and the like, which will hereinafter be cited or identified in the present application, will hereby be incorporated by reference in their entirety in order to describe more fully the state of the art to which the present invention pertains.
A fuel cell is attractive as a power supply to supply power to portable electronic devices such as note-type personal computers, electronic musical instruments and PA systems, instead of secondary batteries such as lithium ion battery and nickel hydrogen battery. The fuel cell is designed to continue supplying power with receiving a supply of fuel for a longer time as compared to the secondary batteries. It has been considered that a direct methanol fuel cell system is applied as a fuel cell for supplying a power to small electric and electronic devices. The direct methanol fuel cell system includes not only a direct methanol fuel cell but also an auxiliary unit for feeding an air as an oxygen source and a methanol solution as a fuel to the direct methanol fuel cell as well as another auxiliary unit for discharging an exhaust including carbon dioxide and a liquid waste including water as reaction product. The auxiliary units include driving devices such as pumps which generate driving sounds. Japanese Unexamined Patent Applications, First Publications, Nos. 2002-343394, 2003-208910, and 2006-085969 disclose conventional techniques for reducing sounds that have been generated by the auxiliary units.
When the fuel cell is used as a power source for the electronic musical instruments and PA systems, the auxiliary units generate driving sounds that interfere or disturb musical performances. In this case, it is desired to reduce the driving sounds that have been generated by the auxiliary units. Japanese Unexamined Patent Application, First Publication, No. 2002-343394 discloses that an expansion chamber with a large capacity is provided in order to reduce sounds that have been generated by the flow of air. The provision of the expansion chamber increases the dimensions or size of the fuel cell system.
Japanese Unexamined Patent Application, First Publication, No. 2003-208910 discloses optimized arrangements of a fuel tank, fuel cell, a liquid waste tank in order to reduce the leakage of sound noise. This optimization decreases the freedom or flexibility of design of the fuel cell system.
Japanese Unexamined Patent Application, First Publication, No. 2006-085969 discloses optimized position of a suction inlet of a pump in the auxiliary unit, so as to reduce sound noise that has been generated by the pump. This optimization decreases the freedom or flexibility of design of the fuel cell system.
In view of the above, it will be apparent to those skilled in the art from this disclosure that there exists a need for an improved apparatus and/or method. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure.